A White House aide said on Sunday that President Barack Obama plans to attend a memorial service on Wednesday at Fort Hood, the site of a shooting last week that left three soldiers dead and 16 injured.

After presidential adviser Dan Pfeiffer made his remarks on CBS, a Fort Hood spokesman confirmed that there will be a remembrance ceremony that day.

Investigators say an army truck driver, Ivan Lopez, had an argument before opening fire at the Texas post last Wednesday. Lopez shot and killed himself on being challenged by an armed army officer.

Fort Hood's commander has not discussed the cause of the argument – no press conferences were scheduled to be held at the base over the weekend.

On Friday, Lieutenant General Mark Milley said investigators believed Lopez’s mental condition was not a "direct precipitating factor" in the shooting, a day after officials said it appeared to be an underlying factor in the attack.

The attack was the second at the base since 2009, when 13 people were killed in a shooting by an army psychiatrist. In August 2013, Major Nidal Hasan was sentenced to death for the shooting.

It was reported this week that a gun store near the Fort Hood base sold guns to both Lopez and Hasan.